Azacitidine in the 'real-world': an evaluation of 1101 higher-risk myelodysplastic syndrome/low blast count acute myeloid leukaemia patients in Ontario, Canada.

The outcome of myelodysplastic syndrome (MDS) patients with uniformly higher-risk disease treated with azacitidine (AZA) in the 'real-world' remains largely unknown. We evaluated 1101 consecutive higher-risk MDS patients (International Prognostic Scoring System intermediate-2/high) and low-blast count acute myeloid leukaemia (AML; 21-30% blasts) patients treated in Ontario, Canada. By dosing schedule, 24·7% received AZA for seven consecutive days, 12·4% for six consecutive days and 62·9% by 5-2-2. Overall, median number of cycles was 6 (range 1-67) and 8 (range 6-14) when restricted to the 692 (63%) patients who received at least 4 cycles. The actuarial median survival was 11·6 months [95% confidence interval (CI) 10·7-12·4) for the entire cohort and 18·0 months (landmark analysis; 95% CI 16·6-19·1 months) for those receiving at least 4 cycles. There was no difference in overall survival (OS) between the 3 dosing schedules (P = 0·87). In our large 'real-world' evaluation of AZA in higher-risk MDS/low-blast count AML, we demonstrated a lower than expected OS. Reassuringly, survival did not differ by dosing schedules. The OS was higher in the 2/3 of patients who received at least 4 cycles of treatment, reinforcing the necessity of sustained administration until therapeutic benefits are realised. This represents the largest 'real-world' evaluation of AZA in higher-risk MDS/low-blast count AML.